How does scientific progress really happen? To a huge extent it's a genetic process. Ideas float around the community, in numbers far too great for any individual to grasp more than a handful. Each grad student accumulates a different subset, depending on interests, past experience, guidance from advisors, and luck. The same holds for professors and everybody else involved in the vast social enterprise of science.

And then the bundle of notions inside an individual noggin smashes up against a research problem. As with the bundle of genes in a living organism, most of the time the result is failure ... but every once in a while a spark lands on dry kindling and a new fire starts to burn.